As a demand for a large data service such as various multimedia Internet services is increasing in wireless communication, an orthogonal frequency division multiplexing (OFDM) technology and an orthogonal frequency division multiple access (OFDMA) scheme are in the spotlight as a wireless transmission technology capable of satisfying the demand.
The OFDM technology is a multiplexing technology in an aspect of simultaneously transmitting data using multiple channels and is also a kind of modulation technology in an aspect of dividing data and thereby transmitting the data using multiple subcarriers.
The OFDMA scheme is a scheme in which a plurality of users is differently allocated with a set of valid subcarriers and thereby uses the allocated subcarriers instead of a scheme in which a single user exclusively uses all the valid subcarriers.
The OFDM technology or the OFDMA scheme is applied to standards such as an Institute of Electrical and Electronics Engineers (IEEE) 802.16e wireless broadband (WiBro) standard, a mobile worldwide interoperability for microwave access (WiMAX) standard, a wireless local area network (WLAN) standard, a 3rd generation partnership project-long term evolution (3GPP-LTE) standard, and the like.
In the OFDM technology or the OFDMA scheme, a transmitted signal becomes a time domain signal that is inverse fast Fourier transformed (IFFT) based on a symbol unit. The IFFT signal has a characteristic in which magnitude of a signal is not consistently maintained. Due to the above characteristic, a peak to average power ratio (PAPR) is very great in the OFDM technology or the OFDMA scheme compared to other modulation schemes.
Since a PAPR is great in the OFDM technology or the OFDMA scheme, the OFDM technology or the OFDMA scheme may not efficiently use a power amplifier. Accordingly, the OFDM technology or the OFDMA scheme requires a technology to efficiently decrease the PAPR.
A variety of methods, for example, a peak cancellation crest factor reduction (PC-CFR) using a cancellation pulse generator (CPG), filtering, and the like may be employed as a method to decrease a PAPR. However, such method to decrease a PAPR may generate a signal distortion in all the frequency domains using a scheme of removing a predetermined portion of a peak value and the like.